The present invention relates to a hydraulic system construction, and more specifically to a pressure vessel interposed in a hydraulic system.
In hydraulic systems it is frequently desirable to utilize a pressure vessel to dampen sudden peaks in the hydraulic pressure and to compensate for various pressure fluctuations. The pressure vessel is normally connected in a by-pass arrangement with a hydraulic system.
A conventional pressure vessel has a housing which consists of two portions one of which forms an upper chamber and the other forms a lower chamber. The interior chamber of the pressure vessel housing is subdivided by a diaphragm formed of elastic material to constitute the upper gas chamber and the lower liquid chamber. Connecting elements having an opening to receive a liquid medium into the liquid chamber is provided at the bottom of the housing. An inlet for a pressure gas medium is normally arranged in the upper wall surrounding the gas chamber.
A housing including a lower wall and an upper wall attached hereto is known, as for example from the U.S. Pat. No. 3,868,972. The upper wall constituting the upper portion of the housing is outlined by curves of various radii. A gas valve is arranged in the highest area of the curved upper wall. Pressure forces of gas medium exerted on the upper wall are the largest in the highest area of said wall since the liquid medium acting on the flexible partition and displacing gas is directed in an axial direction. This can cause large deformations of the upper wall of the housing and may cause deterioration of a locking element arranged in the pressure gas inlet which leads to a gas leakage from the gas chamber.